15,616 research outputs found
Radial convection of finite ion temperature, high amplitude plasma blobs
We present results from simulations of seeded blob convection in the
scrape-off-layer of magnetically confined fusion plasmas. We consistently
incorporate high fluctuation amplitude levels and finite Larmor radius (FLR)
effects using a fully nonlinear global gyrofluid model. This is in line with
conditions found in tokamak scrape-off-layers (SOL) regions.
Varying the ion temperature, the initial blob width, and the initial
amplitude, we found an FLR dominated regime where the blob behavior is
significantly different from what is predicted by cold-ion models. The
transition to this regime is very well described by the ratio of the ion
gyroradius to the characteristic gradient scale length of the blob.
We compare the global gyrofluid model with a partly linearized local model.
For low ion temperatures we find that simulations of the global model show more
coherent blobs with an increased cross-field transport compared to blobs
simulated with the local model. The maximal blob amplitude is significantly
higher in the global simulations than in the local ones. When the ion
temperature is comparable to the electron temperature, global blob simulations
show a reduced blob coherence and a decreased cross-field transport in
comparison with local blob simulations
Post-harvest sown catch crops – results from two years of organic field trials
Post-harvest sown catch crops should be sown as early as possible in order to obtain maximum biomass and nutrient uptake in the harvested crop, as biomass production decreased by 2-3.5 percent per day, when time of sowing was postponed throughout August. Furthermore, the winter hardy species included in these experiments had a tendency to yield less than the non-winter hardy catch crops. These experiments imply that early sown catch crops may become a biomass supplement for organic biogas production, provided sufficient yields are obtained and costs for harvest, transportation and storage are adequately low
- …